JP2011160634A - Power transmission system and power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a non-contact power transmission method of a magnetic field resonance type in a simple and compact constitution at low cost, while securing a certain power transmission limit distance or more. <P>SOLUTION: A power transmission coil 22 of the power transmission device 11 generates an oscillating electromagnetic field of a resonance frequency therearound on the basis on the alternative current from a power transmission circuit 21 to transmit power. A relay coil 61 relays power by flowing an alternative current by the resonance of the oscillating electromagnetic field around the power transmission coil 22 to cause an oscillating electromagnetic field of substantially the same frequency as the resonance frequency. A power receiving coil 41 of a power receiving device 12 receives power by flowing an alternative current by the resonance of the oscillating electromagnetic field around the relay coil 61 to cause the oscillating electromagnetic field of substantially the same frequency as the resonance frequency, and supplies power to various electronic/electric appliances through the power receiving circuit 42. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power transmission system and a power transmission device, and in particular, a technology that enables a magnetic resonance type non-contact power transmission method to be realized with a low-cost, simple and small configuration while ensuring a certain power transmission limit distance or more. About.

  Conventionally, research and development has been conducted on a method for transmitting power without contact (hereinafter referred to as “contactless power transmission method”). As a typical non-contact power transmission method, an electromagnetic induction type non-contact power transmission method is known (see Patent Document 1). Further, in recent years, a magnetic resonance type non-contact power transmission method that enables long-distance transmission as compared with such an electromagnetic induction type non-contact power transmission method has also appeared (see Patent Document 2).

JP 11-0666250 A JP 2009-501510 A

  However, in recent years, there has been a demand for applying such a non-contact power transmission method to a power supply system of various electronic and electrical devices. In the conventional non-contact power transmission methods including Patent Documents 1 and 2, Can't fully meet the demand. That is, in order to meet such a demand, it is necessary to provide a power system with a simple and small configuration at a low cost while securing a transmission limit distance of several meters. However, even if conventional contactless power transmission methods including Patent Documents 1 and 2 are applied, it is very difficult to implement such a power supply system.

  For example, even if an electromagnetic induction type non-contact power method is simply applied, it is very difficult to secure a transmission limit distance in units of several meters. For this reason, Patent Document 1 proposes a technique for extending a power transmission limit distance by arranging a repeater between a power transmission device and a power reception device. However, since the repeater proposed in this method is an active device having an amplifier and a modulation circuit, the repeater is larger than the power transmission device, and the cost increases accordingly. A power supply system that requires such a repeater is not simple and small, even if it can secure a transmission limit distance of several meters, and is low in cost. It's hard to say.

  On the other hand, for example, by applying a magnetic resonance type non-contact power transmission method, it is possible to secure a power transmission limit distance in units of several meters. However, the power transmission limit distance in the magnetic resonance type non-contact power transmission method is determined by factors such as resonance frequency, coil diameter, Q value, transmission power, and transmission efficiency. For this reason, in order to extend the power transmission limit distance while fixing elements other than the coil diameter, it is necessary to increase the coil diameter accordingly. Therefore, in order to secure a transmission limit distance of several meters, it is necessary to employ a power transmission coil and a power reception coil having a large coil diameter, and it is very difficult to realize a simple and small power supply system. Further, when considered as an application of a power supply system for various electronic and electrical devices, it is not realistic to extend the transmission limit distance at the expense of factors other than the coil diameter. Furthermore, there is currently no suitable method that can extend the power transmission limit distance using other factors.

  Therefore, the present invention has been made in view of such a situation, and the magnetic field resonance type non-contact power transmission method is achieved with a low-cost, simple and small configuration while ensuring a certain transmission limit distance or more. The goal is to make it feasible.

According to a first aspect of the invention,
A power transmission system for transmitting power according to a magnetic field resonance type power transmission method,
An alternating current based on an alternating current power supply flows and generates a vibrating electromagnetic field having a resonance frequency around the power transmission coil,
An alternating current flows due to resonance of the oscillating electromagnetic field around the power transmission coil, and a oscillating electromagnetic field having substantially the same frequency as the resonance frequency is generated around the relay coil, and the relay coil that relays the power;
An alternating current flows due to resonance of the oscillating electromagnetic field around the relay coil, and a oscillating electromagnetic field having substantially the same frequency as the resonance frequency is generated around the receiving coil,
A power transmission system is provided.

According to a second aspect of the invention,
Between the power transmission coil and the power reception coil, n (n is an integer value of 1 or more) relay coils are disposed.
A power transmission system is provided.

According to a third aspect of the present invention,
Each of the n relay coils is disposed such that a distance between adjacent coils is equal to or less than a power transmission limit distance between the power transmission coil and the power reception coil when the relay coil is not present. ing,
A power transmission system is provided.

According to a fourth aspect of the invention,
Each of the n relay coils has a coil diameter substantially the same as the coil diameter of the power transmission coil and the power reception coil, and the distance between adjacent coils is approximately (1/2) of the coil diameter. It is arranged to be a distance more than double,
A power transmission system is provided.

According to a fifth aspect of the present invention,
The power transmission coil, each of the n relay coils, and the power reception coil are arranged in that order so as to be substantially coaxial.
A power transmission system is provided.

According to a sixth aspect of the present invention,
The power transmission coil and the power reception coil are arranged without matching the axes,
The n relay coils are substantially {1 / (n + 1) with respect to an angle formed by a line connecting the centers of the power transmission coil and the power reception coil passing through the center and the power transmission coil and the power reception coil. )} Are shifted by a multiple of the angle,
A power transmission system is provided.

According to a seventh aspect of the present invention,
A power transmission device that transmits power according to a magnetic field resonance type power transmission method,
An alternating current based on an alternating current power supply flows and generates a vibrating electromagnetic field having a resonance frequency around the power transmission coil,
An alternating current flows due to resonance of the oscillating electromagnetic field around the power transmission coil, and a oscillating electromagnetic field having substantially the same frequency as the resonance frequency is generated around the relay coil, and the relay coil that relays the power;
A power transmission device is provided.

  According to the present invention, a magnetic resonance type non-contact power transmission method can be realized with a low-cost, simple and small configuration while ensuring a certain power transmission limit distance or more.

It is a block diagram which shows the structure of the basic power transmission system for demonstrating the principle of the power transmission system of embodiment of this invention. It is a block diagram which shows the structure of the electric power transmission system of the 1st Embodiment of this invention. It is a figure which shows the external appearance structure of the relay coil of the electric power transmission system of FIG. It is a figure which shows the external appearance structure of the power transmission coil of the electric power transmission system of FIG. It is a block diagram which shows the structure of the electric power transmission system of the 2nd Embodiment of this invention. In the power transmission system of FIG. 5, it is a figure explaining the arrangement | positioning form of a relay coil in case the axis | shaft of a power transmission coil and a receiving coil does not correspond. In the power transmission system of FIG. 5, it is a figure explaining the arrangement | positioning form of a relay coil in the case where the axis | shafts of a power transmission coil and a receiving coil do not correspond, Comprising: FIG. In the power transmission system of FIG. 5, it is a figure explaining the arrangement | positioning form of a relay coil in the case where the axis | shafts of a power transmission coil and a receiving coil do not correspond, Comprising: FIG. 6 and FIG.

  First, in order to facilitate understanding of the present invention and to clarify the background thereof, electric power to which a magnetic resonance type contactless power transmission method, which is the basis of the power transmission system according to the embodiment of the present invention, is applied. A transmission system (hereinafter referred to as “basic power transmission system”) will be described with reference to FIG.

  FIG. 1 is a block diagram showing a configuration of a basic power transmission system.

  The basic power transmission system includes a power transmission device 11 and a power reception device 12. The power transmission device 11 and the power reception device 12 are physically separated from each other and separated by a certain distance equal to or less than the power transmission limit distance L.

The power transmission device 11 includes a power transmission circuit 21 and a power transmission coil 22. The power transmission circuit 21 includes an oscillation circuit 31 connected to a commercial AC power supply or the like (not shown). The power transmission coil 22 includes a power input coil 32 to which power is input by the oscillation circuit 31 and a resonance coil 33 that magnetically resonates with the power receiving side. The resonance coil 33 has a resonance frequency f ₀ represented by the following equation (1).

・・・（１）
式（１）において、Ｌは、共鳴コイル３３のインダクタンスを示している。Ｃは共鳴コイル３３の両端部が所定の距離だけ離間して配置されることにより生ずる浮動容量を示している。即ち、共鳴コイル３３の等価回路は、図１に示すように、このようなインダクタンスＬとキャパシタＣとが接続されたＬＣ回路になる。ただし、Ｃは、浮動容量の代わりに、共鳴コイル３３に接続したコンデンサ素子の容量としてもよい。

... (1)
In Expression (1), L indicates the inductance of the resonance coil 33. C indicates a floating capacitance generated when both ends of the resonance coil 33 are spaced apart from each other by a predetermined distance. That is, the equivalent circuit of the resonance coil 33 is an LC circuit in which such an inductance L and a capacitor C are connected as shown in FIG. However, C may be the capacitance of the capacitor element connected to the resonance coil 33 instead of the floating capacitance.

  The power receiving device 12 includes a power receiving coil 41 and a power receiving circuit 42. The power receiving coil 41 includes a resonance coil 51 that magnetically resonates with the power transmission side, and a power extraction coil 52 from which power is extracted by the power reception circuit 42. The power receiving circuit 42 includes a bridge rectifier circuit 53 and a smoothing capacitor 54. In the bridge rectifier circuit 53, the power extraction coil 52 is connected to the input terminal, and the smoothing capacitor 54 is connected to the output terminal. Both ends of the smoothing capacitor 54 are also connected to various electronic / electrical devices (not shown) that are DC driven.

  The basic power transmission system having such a configuration operates as follows.

That is, in the power transmission device 11, the oscillation circuit 31 is driven by electric power supplied from a commercial AC power supply or the like (not shown). The oscillation frequency of the oscillation circuit 31 is set to the resonance frequency f ₀ of the resonance coil 33 described above. When an alternating current output from the oscillation circuit 31 by the oscillation operation flows through the power input coil 32, an alternating oscillating electromagnetic field having a frequency f ₀ is generated around the power input coil 32. Then, an alternating current flows through the resonance coil 33 by being induced by an oscillating electromagnetic field around the power input coil 32. As a result, an oscillating electromagnetic field having a resonance frequency f ₀ is generated around the resonance coil 33.

In the power receiving device 12, the equivalent circuit of the resonance coil 51 is also an LC circuit similar to the equivalent circuit of the resonance coil 33, as shown in FIG. For this reason, alternating current flows through the resonance coil 51 due to resonance of the oscillating electromagnetic field around the resonance coil 33 on the power transmission device 11 side. In other words, wireless non-radiation type energy transfer using the electromagnetic field mode of vibration resonance is performed from the resonance coil 33 to the resonance coil 51, whereby alternating current flows through the resonance coil 51. As a result, an oscillating electromagnetic field having substantially the same frequency as the resonance frequency f ₀ is generated around the resonance coil 51. Then, an alternating current flows through the power extraction coil 52 by being induced by this oscillating electromagnetic field. The alternating current flowing through the power extraction coil 52 is full-wave rectified in the bridge rectifier circuit 53. The full-wave rectified current (pulsating current) is smoothed by the smoothing capacitor 54 and supplied to various electronic devices (not shown) that are DC driven.

  In this manner, in the basic power transmission system, power is supplied from the power transmission device 11 to the power reception device 12 in a contactless manner due to magnetic field resonance.

Here, as described above in the section “Problems to be Solved by the Invention”, the power transmission limit distance L of the basic power transmission system (hereinafter referred to as “basic power transmission limit distance L”) is the resonance frequency f _0. It is determined by factors such as the coil diameter, Q value, transmitted power, and transmission efficiency of the power transmission coil 22 and the power reception coil 41. For this reason, in order to extend the basic power transmission limit distance L while fixing elements other than the coil diameter, it is necessary to increase the coil diameter accordingly. Therefore, in order to secure the transmission limit distance L of several meters in the configuration of the basic power transmission system, it is necessary to prepare the power transmission coil 22 and the power reception coil 41 having a large coil diameter. It is very difficult to realize the system. Further, when considered as an application of a power supply system for various electronic and electrical devices, it is not realistic to extend the power transmission limit distance L at the expense of factors other than the coil diameter.

  Therefore, the magnetic field resonance type power system to which the embodiment of the present invention is applied is designed to ensure a transmission limit distance longer than the basic transmission limit distance L, for example, a transmission limit distance of several meters. 2 is configured.

  FIG. 2 is a block diagram illustrating a configuration of the power transmission system according to the first embodiment of this invention.

  In FIG. 2, portions corresponding to those in FIG. Since these portions have been described with reference to FIG. 1, description thereof will be omitted as appropriate.

  The power transmission system illustrated in FIG. 2 includes a power transmission device 11 and a power reception device 12 in the same manner as the basic power transmission system illustrated in FIG. The power transmission system illustrated in FIG. 2 further includes a resonance coil 61 (hereinafter referred to as “relay coil 61”) disposed between the power transmission device 11 and the power reception device 12.

  FIG. 3 shows an external configuration of the relay coil 61. That is, FIG. 3A shows a front view of the external configuration of the relay coil 61, and FIG. 3B shows a side view of the external configuration of the relay coil 61. FIG. 4 shows an external configuration of the power transmission coil 22 of the power transmission device 11. That is, FIG. 4A shows a front view of the external configuration of the power transmission coil 22, and FIG. 4B shows a side view of the external configuration of the power transmission coil 22.

3 and 4, it can be seen that the relay coil 61 has the same configuration as the resonance coil 33 of the power transmission coil 22. That is, both the relay coil 61 and the resonance coil 33 are configured by arranging substantially the same material and the same thickness of conductive wire in a substantially circular manner about six turns. As a result, the relay coil 61 has substantially the same inductance L as the resonance coil 33 and has the same floating capacitance C as the resonance coil 33. That is, the equivalent circuit of the relay coil 61 is the same LC circuit as the equivalent circuit of the resonance coil 33 shown in FIG. Therefore, the relay coil 61 has substantially the same resonance frequency as the resonance frequency f ₀ of the resonance coil 33.

  Although not shown, the power reception coil 41 of the power reception device 12 also has the same external configuration as the power transmission coil 22 of FIG. That is, in this embodiment, the diameters of the relay coil 61, the resonance coil 33 of the power transmission coil 22, and the resonance coil 51 of the power reception coil 41 are substantially the same.

  The power transmission system of the present embodiment having such a configuration operates as follows.

That is, the power transmission device 11 performs the above-described operation as the operation of the basic power transmission system. As a result, an oscillating electromagnetic field having a resonance frequency f _{0 represented by} the above-described equation (1) is generated around the resonance coil 33.

Here, as described above with reference to FIGS. 3 and 4, the equivalent circuit of the relay coil 61 is also an LC circuit similar to the equivalent circuit of the resonance coil 33. For this reason, alternating current flows through the relay coil 61 due to resonance of the oscillating electromagnetic field around the resonance coil 33 on the power transmission device 11 side. In other words, wireless non-radiation type energy transfer using the electromagnetic field mode of vibration resonance is performed from the resonance coil 33 to the relay coil 61, whereby alternating current flows through the relay coil 61. As a result, an oscillating electromagnetic field having substantially the same frequency as the resonance frequency f ₀ is generated around the relay coil 61.

In the power receiving device 12, alternating current flows through the resonance coil 51 due to resonance of the oscillating electromagnetic field around the relay coil 61. In other words, a wireless non-radiative energy transfer using the electromagnetic field mode of vibration resonance is performed from the relay coil 61 to the resonance coil 51, whereby an alternating current flows through the resonance coil 51. As a result, an oscillating electromagnetic field having substantially the same frequency as the resonance frequency f ₀ is generated around the resonance coil 51. Thereafter, the power receiving apparatus 12 supplies the electric power to various electronic electric devices (not shown) that are DC-driven by performing the above-described operation as the operation of the basic power transmission system.

  In this manner, in the power transmission system of the present embodiment, power is supplied from the power transmission device 11 to the power reception device 12 through the relay coil 61 in a contactless manner due to magnetic field resonance.

  In the power transmission system of the present embodiment that operates as described above, as shown in FIG. 2, the power transmission coil 22 of the power transmission device 11, the relay coil 61, and the power reception coil 41 of the power reception device 12 are connected to the basic power transmission limit distance L. Power transmission is made possible by arranging them so as to be substantially coaxial with being spaced apart from each other. That is, the power transmission limit distance between the power transmission device 11 and the power reception device 12 can be extended to approximately twice the basic power transmission limit distance L (≈2L).

  In other words, when the maximum separation distance between the power transmission device 11 and the power reception device 12 is determined to be a fixed distance T (T is an arbitrary positive value) according to specifications or the like, in the basic power transmission system, the basic power transmission limit distance L is a fixed distance T (L = T). On the other hand, in the power transmission system of the present embodiment, the basic power transmission limit distance L is approximately (1/2) times the fixed distance T (L≈T / 2), so the basic power transmission limit distance L is shortened. can do. Here, the size of the coil diameter of the power transmission coil 22 and the power reception coil 41 is not the fixed distance T but depends on the basic power transmission limit distance L as described above. Therefore, in the power transmission system of the present embodiment, it is possible to employ the power transmission coil 22 and the power reception coil 41 having a smaller coil diameter than the basic power transmission system. As a result, the power transmission system of the present embodiment can be realized with a low-cost, simple and small configuration. However, in order to avoid interference between the coils, the distance between the relay coil 61 and the power transmission coil 22 or the power reception coil 41 is approximately (1/2) times or more of each coil diameter, and is approximately (L × 0). .9) The following distance is preferred.

  Here, the power transmission system of the present embodiment includes a relay coil 61 that does not exist in the basic power transmission system. However, as described above with reference to FIG. 3, the relay coil 61 has a passive and simple configuration that does not have any circuit or power supply, and thus the power transmission system of the present embodiment is low-cost and simple. This is no obstacle to the realization of a small configuration.

  Rather, since the relay coil 61 having such a passive and simple configuration can be easily disposed at various places, the following effects can be obtained. That is, the user can easily attach the relay coil 61 to, for example, the back of a desk, or attach or embed the relay coil 61 on a wall, door, ceiling, floor, or the like. As a result, the user can achieve an effect that the power receiving device 12 can be easily arranged at a desired position regardless of the arrangement position of the power transmitting device 11. This effect will be specifically described below.

  For example, since the power transmission device 11 is connected to a commercial AC power supply or the like and receives power supply, it is disposed around the commercial AC power supply or the like. On the other hand, since the power receiving device 12 supplies electric power to various electronic electrical devices, a desired arrangement position of the power receiving device 12 for the user is a place around the various electronic electrical devices. Specifically, for example, when a commercial AC power supply exists under a desk, the power transmission device 11 is disposed on a floor or a shelf under the desk. On the other hand, for example, various electronic and electrical devices used by the user are arranged on the desk, and therefore the desired arrangement position of the power receiving device 12 for the user is on the desk. In this case, in the basic power transmission system, even if the distance between the power transmission device 11 and the power reception device 12 exceeds the basic power transmission limit distance L and power transmission becomes impossible or power transmission is possible, the power transmission efficiency is high. It may get worse. In such a case, by attaching or embedding the relay coil 61 to the back of the desk or including it (including putting it in a drawer, etc.), the power transmission limit distance extends to approximately twice the basic power transmission limit distance L (≈2L). The power transmission efficiency is improved and power transmission is possible in a good state.

  In addition, for example, there is a desire to transmit power to various electronic electrical devices existing in a plurality of rooms with a single power source. That is, for the user, the power transmission device 11 is connected to a commercial AC power source or the like existing in a predetermined room, and the power reception device 12 is arranged in a desired place in a room different from the predetermined room. There is a desire to supply electric power to various electronic and electrical devices in the other room. However, even if the basic power transmission system is adopted, it is very difficult to meet such a demand. On the other hand, it becomes possible to meet such a demand by adopting the power transmission system of the present embodiment. That is, for example, even if the power transmitting device 11 and the power receiving device 12 are separately provided in two adjacent rooms, the relay coil 61 is provided on a door or wall that separates the two rooms, or on a ceiling or floor. Thus, power transmission from the power transmission device 11 to the power reception device 12 in the adjacent room becomes possible. In this way, it is possible to meet the demand to transmit power to various electronic and electrical devices existing in multiple rooms with a single power source. As a result, the power supply system can be saved, and the installation cost of various electronic and electrical devices can be reduced. You can save.

  As described above, by adopting the power transmission system of the present embodiment, the magnetic resonance type non-contact power transmission method is low-cost, simple and compact configuration while ensuring a certain transmission limit distance or more. Can be realized.

  It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.

  For example, in the above-described embodiment, only one relay coil 61 is disposed. However, the number of relay coils 61 is not particularly limited to the above-described example, and as shown in FIG. It may be an arbitrary integer value of 1 or more. In the above-described embodiment, the relay coil 61 and the resonance coil 33 are both made of substantially the same material and substantially the same shape. However, if the resonance coil 61 and the resonance coil 33 can have substantially the same resonance frequency, the material and shape are changed. It is not limited to.

  FIG. 5 is a block diagram showing the configuration of the power transmission system according to the second embodiment of this invention.

  In FIG. 5, portions corresponding to those in FIG. Since these portions have been described with reference to FIG. 2, description thereof will be omitted as appropriate.

  The power transmission system illustrated in FIG. 5 includes a power transmission device 11 and a power reception device 12, similarly to the power transmission system illustrated in FIG. 2. The power transmission system illustrated in FIG. 5 further includes n relay coils 61-1 to 61-n disposed between the power transmission device 11 and the power reception device 12. Hereinafter, when it is not necessary to individually distinguish the relay coils 61-1 to 61-n, these are collectively referred to as “relay coils 61”.

  In this case, for example, the n relay coils 61 are arranged substantially coaxially at equal intervals of about the basic power transmission limit distance L, so that power transmission between the power transmission device 11 and the power reception device 12 is performed as shown in FIG. The limit distance can be extended to approximately (n + 1) times {≈L × (n + 1)} the basic power transmission limit distance L.

  In other words, when the maximum separation distance between the power transmission device 11 and the power reception device 12 is determined to be the above-described fixed distance T according to specifications or the like, in the power transmission system illustrated in FIG. Is approximately {1 / (n + 1)} times the fixed distance T {L≈T / (n + 1)}. That is, the basic power transmission limit distance L can be shortened as the number n of the relay coils 61 is increased. Here, the coil diameters of the power transmission coil 22, the n relay coils 61, and the power receiving coil 41 depend on the basic power transmission limit distance L as described above, not the fixed distance T. Therefore, each coil diameter can be reduced as the number n of relay coils 61 is increased. As a result, the power transmission system can be realized with a much lower cost, simple and small configuration. However, in order to avoid interference between the coils, the distance between the relay coil 61 and an adjacent coil (another relay coil 61, power transmission coil 22, or power reception coil 41) is approximately (1 / 2) A distance that is greater than or equal to twice and less than or equal to (L × 0.9) is preferred.

  In this way, by appropriately setting the number n of the relay coils 61 according to specifications required for the power transmission system, for example, various specifications such as a transmission limit distance, cost, size, and the like, power transmission that satisfies the specifications is achieved. It becomes possible to easily and appropriately embody the system.

  Further, for example, in the above-described embodiment, the power transmission coil 22 and the power reception coil 41 are disposed so as to be substantially coaxial, but the relationship between the placement locations is not particularly limited to the above-described example. For example, as shown in FIGS. 6 to 8, the power transmission coil 22 and the power reception coil 41 can be freely arranged so that an angle and an axis shift are generated without matching the axes of each other. In this case, the arrangement location of the relay coil 61 is not particularly limited, but the arrangement location shown in FIGS. 6 to 8 is preferable in consideration of power transmission efficiency and the like.

  Each of FIGS. 6 to 8 is a diagram illustrating each of three forms of the arrangement form of the relay coil 61 in the case where the axes of the power transmission coil 22 and the power reception coil 41 do not match in the power transmission system of FIG. .

  As shown in FIGS. 6 to 8, each of the n relay coils 61 includes a line connecting the centers of the power transmission coil 22 and the power reception coil 41 (a chain line in the figure) passing through the substantial center, and power transmission. The angle between the coil 22 and the power receiving coil 41 may be shifted by approximately {1 / (n + 1)} times and arranged at equal intervals equal to or less than the basic power transmission limit distance L. However, also in this case, in order to avoid interference between the coils, the distance between the relay coil 61 and the adjacent coil (another relay coil 61, the power transmission coil 22, or the power reception coil 41) is the diameter of each coil. A distance of approximately (½) times or more and approximately (L × 0.9) or less is preferable.

  In this way, the user can freely arrange each of the n relay coils 61 independently. As a result, the above-described effect that the power receiving device 12 can be easily arranged at a desired position regardless of the arrangement position of the power transmitting device 11 becomes more remarkable.

  In the present specification, the term system refers to an overall device that includes a plurality of devices, a plurality of units, and the like. In other words, the method of grasping the components of the power transmission system according to the embodiment of the present invention is based on the grasp of the above-described grasping that the power transmission device 11 includes the relay portion including the n relay coils 61 and the power reception device 12. There is no particular need to adopt a method. That is, it may be grasped that the power transmission device is configured by the device called the power transmission device 11 in the above-described example and at least one of the n relay coils 61. Similarly, in the above-described example, it may be grasped that the power receiving device is configured by the device called the power receiving device 12 and at least one of the n relay coils 61.

  DESCRIPTION OF SYMBOLS 11 ... Power transmission apparatus 11 ... Power receiving apparatus, 21 ... Power transmission circuit, 22 ... Power transmission coil, 31 ... Oscillation circuit, 32 ... Power supply coil, 33 ... Resonance coil, 41 ... Receiving coil 41 ... Receiving circuit, 51 ... Resonance coil, 52 ... Power extraction coil, 53 ... Bridge rectifier circuit, 54 ... Smoothing capacitor, 61 ... Relay coil

Claims (7)

A power transmission system for transmitting power according to a magnetic field resonance type power transmission method,
An alternating current based on an alternating current power supply flows and generates a vibrating electromagnetic field having a resonance frequency around the power transmission coil,
An alternating current flows due to resonance of the oscillating electromagnetic field around the power transmission coil, and a oscillating electromagnetic field having substantially the same frequency as the resonance frequency is generated around the relay coil, and the relay coil that relays the power;
An alternating current flows due to resonance of the oscillating electromagnetic field around the relay coil, and a oscillating electromagnetic field having substantially the same frequency as the resonance frequency is generated around the receiving coil,
A power transmission system comprising: Between the power transmission coil and the power reception coil, n (n is an integer value of 1 or more) relay coils are disposed.
The power system according to claim 1. Each of the n relay coils is disposed such that a distance between adjacent coils is equal to or less than a power transmission limit distance between the power transmission coil and the power reception coil when the relay coil is not present. ing,
The power system according to claim 2. Each of the n relay coils has a coil diameter substantially the same as the coil diameters of the power transmission coil and the power reception coil, and the distance between adjacent coils is approximately (1/2) times the coil diameter. It is arranged to be the above distance,
The power system according to claim 3. The power transmission coil, each of the n relay coils, and the power reception coil are arranged in that order so as to be substantially coaxial.
The power system according to claim 3 or 4. The power transmission coil and the power reception coil are arranged without matching the axes,
The n relay coils are substantially {1 / (n + 1) with respect to an angle formed by a line connecting the centers of the power transmission coil and the power reception coil passing through the center and the power transmission coil and the power reception coil. )} Are arranged at substantially equal intervals, shifted by multiple times.
The power system according to claim 3 or 4. A power transmission device that transmits power according to a magnetic field resonance type power transmission method,
An alternating current based on an alternating current power supply flows and generates a vibrating electromagnetic field having a resonance frequency around the power transmission coil,
An alternating current flows due to resonance of the oscillating electromagnetic field around the power transmission coil, and a oscillating electromagnetic field having substantially the same frequency as the resonance frequency is generated around the relay coil, and the relay coil that relays the power;
A power transmission device comprising:

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